1. Field of the Invention
The present invention relates generally to adjustable clamps and more particularly to portable, carpenter's clamps suitable for holding work pieces such that they may be sawn without being marred.
2. Description of the Background Art
Adjustable clamps are commonly used mechanisms for securing a piece of work in a fixed position such that various tools may be applied to it and the contours of the work modified. The classic C-clamp is adjusted by turning a screw bolt to which a holding surface is attached. That surface is placed in opposition to a stationary holding surface at the opposite end of the clamp and the work is placed in between. The screw bolt is turned such that the work is held between the two opposed holding surfaces.
Toggle clamps are used in industry for holding the same size work piece for either repeated machining operations or the same operation on many identical pieces. Thus, these toggle clamps are adjusted once for a large run of similar workpieces. Attempts to adapt the toggle clamp to the home workshop have encountered a number of problems in that the home workshop requires a clamp capable of use with a number of problems in that the home workshop requires a clamp capable of use with a number of differently sized pieces and a variety of operations. The existing toggle clamps are difficult to adjust and have a limited range of adjustment, thus making them unsuitable for applications where a large number of variously sized and shaped workpieces are employed.
The present invention is more suitable for home use in that it adjusts rapidly to any size of workpiece within the capacity of the clamp. The invention also provides a safe and comfortable handle. The gripping of the handle also serves to retain the lever in its closed position during use.
The C-clamp has been improved on by the addition of either a toggle or cam assembly attached to a handle, placed such that the operation of the handle urges one holding surface toward the other, thus applying pressure to the work and gripping it. An additional improvement to the C-clamp has been the use of a slide-bar assembly wherein one holding surface is free to travel along a portion of the frame. Pressure applied to the holding surface induces a bias in the holding arm, thereby causing a binding of the holding arm of the slide-bar.